Lubricant



Patented Jim. 23, 1940 uui Eo STATES LUnmcAN'r James W. Johnson, Philadelphia} Pa., assignor The Atlantic Refining Company, Philadelphia, Pa., a corporation of Pennsylvania No Drawing. Application May 12, 10st, Serial No. 207,508

6 Claims.

'I hepresent invention relates to improvements in lubricating oils and more particularly to a method for increasing their lubricity or oiliness.

It has generally been known that the quality of a lubricating oil depends on some properties other than the viscosity of the hydrocarbon oil. This has been found to be particularly true when the'lubricant is used under conditions of thin film or boundary lubrication in which the layer of lubricating. oil between the rubbing surfaces is very thin. It has been found that some oils act as better lubricants than others under conditions of'boundary lubrication even though their viscosities at the temperature of useare substantially the same. The property of one oil which makes it a better lubricant than another under these conditions, particularly inlowering friction and/or wear, has beendesignated as oiliness,.

It is therefore an object of. this invention to increase the oiliness of paraflin base, mixed base and naphthene base lubricating oils by the additionthereto of a relatively small proportion of a material which is active to improve this property without objectionably afiectingother desirable properties thereof. More particularly, the presentinvention relates to the production of an improved lubricating oil of this type having increased oiliness" by the addition thereto of' a urethane. .By the term urethane is meant the esters of carbamic acid and substituted deriva tives thereof. I In accordance with my invention, a urethane or a mixture of urethanes is admixed with a lubricating oil in quantities of the order of 0.1%,

0.25%, 0.5% or 1% by weightor more, depending upon the degree of improvement desired. Among the urethanes which may be suitably employed are-methyl urethane, ethyl urethane, ethylene urethane, propyl urethane, butyl urethane, amyl urethane, allyl urethane, acetyl urethane, nitrosourethane, nitrosomethyl urethane, nitro urethane, methyl nitro urethane and the like.

In order te determine the effectiveness of the vurethanes as addition agents for improving the oiliness" of lubricatingoil. small quantities were added to a hydrocarbon oil having a Saybolt Universal viscosity of 376 seconds at 100 R, an A. P. I. gravity of 21.9", and containing 3% by volume of tricresyl phosphate. The latter material has little or no effect upon the ,oiliness" but functions to increase the film strength of the oil and permitfioiliness" tests to be carried on under heavier loads than the hydrocarbon lubricating oil. per se, is able to withstand. The determination of the oiliness" or lowering of the coemcient of friction was made in an Almen extreme pressure'lubricant testing machine at 200 R. P. M., the load being expressed in lbs/sq. in. projected bearing area and the oiliness as ameasure of the friction expressed in pound-feet torque.

' Load naming-5' Lubricant 10,000 15,000 20,000 22,000

1 LIL-Ft. Lit-rt. un. L L-Ft. Oil-+37 tricmsyl phosphate" 36 48 68 0il+3 o tricmsyl phosphate +1 urethane 28 38 49 53 0ii+ a tricresyl phosphate a u urothane 30 39 47 40 Oii+3% tricresyl h hate +0.5% butyl at yl mido di-earborylate 30 41 48 From the above table it will be seen that the addition or a urethane or substituted methane to .a lubricating oil improves the oi1iness" or reduces friction to a substantial extent. It is not necessary that the lubricant contain a film strength addition agent such as tricresyl phosphate, since an unblended hydrocarbon lubricating oil will exhibit a marked improvement in oiliness simply upon the addition of a urethane or substituted urethane such as hereinbefore mentioned. In the event that increased film strength is likewise desired, there may be added to the oil-urethane blend, a quantity of film strength agent such as aliphatic or aromatic phosphates, phosphites or thiophosphates, chlorinated esters or chlorinated hydrocarbons, or other known agents for improving film strength.

For brevity, in the appended claims, the term a urethane is to be understood to comprehend urethane and substituted urethanes, or mixture of two or more of them.

What I claim is:

1. A lubricant comprising a hydrocarbon oil and a small amount of a urethane.

\ 2. A lubricant comprising a hydrocarbon oil and less than substantially 1% by weight of a urethane. Y

3. A lubricant comprising a hydrocarbon oil and a small amount of an alkyl urethane.

4. A lubricant comprising a hydrocarbon oil and a small amount of ethyl urethane.

5. A lubricant comprising a hydrocarbon oil and a small amount of butyl urethane.

6. A lubricant comprising a hydrocarbon oil and a small amountof butyl ethyl imido dicarboxylate.

JAMES W. JOHNSON. 

